The coronavirus conundrum: when to press the panic button

We have become very good at detecting risk, but it's impossible to know if this latest virus will be another Sars or disappear

A medical worker disinfects cages containing civet cats at a market selling wild animals in Guangzhou, China, during the Sars epidemic, which was also caused by a coronavirus. Photograph: Chang Feng/EPA

In case, like Hedren, you've been marooned in Bodega Bay and missed the update, the coronavirus, which takes its name from the menacing, crown-like spikes on its surface, first blipped on the HPA's radar in September, when a 49-year-old Qatari man was admitted to intensive care at St Thomas' Hospital with renal failure. Now the virus seems to have been transmitted to a new patient at another hospital, providing "strong evidence for person-to-person transmission".

Never mind that there have been a total of just three confirmed cases in the UK and 11 worldwide, half those infected have died and, as there is no vaccine, health officials are "worried". They are worried not least because we have been here before: in 2003, to be precise, when severe acute respiratory syndrome (Sars), also caused by a coronavirus, suddenly emerged from Guangdong, China, sparking an epidemic that resulted in 1,000 deaths worldwide and grounded planes from Hong Kong to Toronto.

On that occasion, civet cats – a popular delicacy in Chinese animal markets – were to blame; this time the animal reservoir is thought to be bats. But the truth is that no one knows for certain, least of all the scientists whose job it is to keep tabs on new pathogens and alert us to the threat before they can be reprimanded for not speaking up sooner.

And that's the dilemma: press the panic button too early and you risk being labelled a wolf-crier. Do it too often and when a real wolf comes along – albeit in the guise of a bird, cat or bat – no one will believe you.

For all the current fuss about the coronavirus, the pathogen that still keeps most scientists awake at night is H5N1 bird flu, a virus that first emerged in Hong Kong around the same time as Sars, and which has been causing deaths every year since. And let's not forget about ebola, a Hammer Horror virus that reduces victims' organs to a bloody pulp and is also thought to be spread by bats (truly, Hitchcock is spoilt for choice).

Part of the problem is that we have become almost too good at detecting these risks. To keep tabs on exotic pathogens, the World Health Organisation now routinely trawls the internet for reports of unusual disease outbreaks in remote jungle regions. Meanwhile, in Africa, health workers are being encouraged to use SMS to text clinical data from the bush in real time.

For the most part, these efforts are welcome. However, the paradox is that the digital technologies that enable us to monitor the emergence of exotic diseases and take action to prevent pandemics are the very same technologies that spread fear.

This is arguably exactly what happened in the spring of 2009, when the WHO, already on high alert over bird flu, began picking up electronic chatter about an unusual flu-like illness in the Yucatan. Within weeks, "Mexican" swine flu had sparked a series of escalating pandemic alerts, whipping up needless hysteria and triggering the production of billions of dollars' worth of vaccines that had to be junked as soon as the pandemic fizzled out.

Of course, the coronavirus is a very different animal from swine flu. Judging by the messages issued by health experts, scientists have learned a lot from 2009. For instance, Professor John Oxford, who was responsible for sounding some of the direst warnings five years ago, told the BBC that the coronavirus "doesn't raise too many alarm bells" as the latest patient seemed to have got it from his father, meaning transmission probably required close contact. "If it was somebody who was not related – or a nurse or a doctor – that would be a lot more serious," said Oxford.

So that's all right then: the coronavirus is only a little bit infectious – unless, of course, it isn't.